The Spatial Proximity
Tool, a new computer technology developed as a part of Silent Spring
Institute's Cape Cod Breast Cancer and Environment Study, links individual
addresses with historical environmental data. Announced in a paper published
by the Journal of Exposure Analysis and Environmental Epidemiology,
the software can determine distance and direction from areas where a
pesticide was used and a pesticide's persistence in the environment.

This exposure assessment
tool can help women who have been diagnosed with breast cancer, but
didn't know they were at risk. Jane Chase, the first in her family to
be diagnosed with breast cancer, is concerned. "I've lived in my
home since 1957. It's next to a marsh that could have been sprayed for
mosquitoes. But I have no idea what pesticides were used or what long-term
effects they may have."

The Silent Spring
Institute's Cape Cod Breast Cancer and Environment Study is investigating
the relationship between the environment and breast cancer on Cape Cod,
MA, a region with a history of higher incidence of the disease. Information
from interviews with 2,100 women participating in this study is combined
with data from the Spatial Proximity Tool to provide a more precise
picture of women's pesticide exposures.

Researchers from
Silent Spring Institute conducted extensive fieldwork, which yielded
information about historical pesticide practices and maps used by pilots
for aerial spraying programs dating back to the 1950s. The data is integrated
using a computer mapping technology, geographic information system (GIS),
which combines and layers multiple data sources. Institute researchers
estimated the relative intensities of pesticide exposures between 1948
and 1995 at each of the participants' Cape Cod residences, and found
that, during these years, more than two dozen chemicals, including DDT,
dieldrin, and Sevin® were applied on Cape Cod.

Dr. Julia G. Brody,
executive director of Silent Spring Institute and lead author on the
study, describes what this tool could mean to concerned residents and
to researchers in the field of epidemiology. "The ability to efficiently
capture a woman's pesticide exposures dating back to earlier years is
key to learning how pollutants affect cancer risk. Our ultimate goal
is to discover risk factors we can change. We owe it to our daughters
to find ways to bring down breast cancer risk."